1. Field of the Invention
The present invention relates to an electronic apparatus such as a disk reproducing apparatus in which at the time of shifting to a standby mode, a voltage of an operating power source supplied to a microcomputer for control is rendered lower than a voltage at the time of an operating mode.
2. Description of the Related Art
Consumer-oriented equipment such as a DVD reproducing apparatus is configured so that instructions of power-on from a front panel or a remote controller can be accepted even at the time of shifting to a standby mode which is a power-off state. On the contrary, reduction in power consumption in the standby mode is desired. For this purpose, conventionally, in the case of shifting to the standby mode, an operating power source is supplied to a microcomputer for control and supply of the operating power source to other main circuit parts is stopped and thereby power consumption in the standby mode is reduced (first related art).
The following art is proposed (second related art). That is, in this art, a transformer on which two primary coils and two secondary coils are wound is provided. Also, a rectification smoothing output of one of the two secondary coils is used as an operating power source of a microcomputer and a rectification smoothing output of the other of the secondary coils is used as an operating power source of a main circuit part. Then, at the time of shifting to a standby mode, a power source is supplied to only the one side of the primary coils and supply of the power source to the other side of the primary coils is stopped. Also, a path of supply of the operating power source to the main circuit part is broken. Therefore, it is constructed so that even at the time when it shifts to the standby mode and power consumption of the secondary side reduces, reduction in conversion efficiency of the transformer is prevented and power consumption in the standby mode is reduced (for example, see JP-A-2000-14005).
The following art is proposed (third related art). That is, in this art, a transformer in which a tap is formed in a primary coil is provided. Then, it is constructed so that at the time of shifting to an operating mode, one path of a power source is connected to the tap and at the time of shifting to a standby mode, the one path is switched and connected to the side of an end terminal of the primary coil. In other words, it is constructed so that the number of windings of the primary coil in the standby mode becomes more than the number of windings of the primary coil in the operating mode. Because of this, a voltage generated in a secondary coil at the time of the standby mode becomes lower than a voltage generated in the secondary coil at the time of the operating mode. As a result of that, power consumption at the time of the standby mode of a main circuit part using a DC output obtained by rectifying and smoothing an output of the secondary coil as an operating power source is rendered lower than power consumption at the time of the operating mode. Also, at the time of shifting to the standby mode, power consumption of a constant voltage circuit for generating an operating power source for a microcomputer for control is also rendered lower than power consumption at the time of the operating mode (for example, see JP-A-2000-125468).